Fusible link
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The fusible plug (also known as a fusible plug) is a safety mechanism for pressure vessels .
Fusible plugs are typically made of bronze , brass or gunmetal and have a conical hole. The hole is soldered shut. When the solder reaches the melting temperature, the screw opens and the pressurized medium flows out.
Applications
- Steam boiler
- Air conditioners
- Transport and storage of liquid gas (a slow, controlled escape is better than an explosion (see also BLEVE ))
- Fluid couplings in EX areas (in the event of an overload, the operating fluid heats up, the fusible plug allows the operating fluid to escape and thus separates the drive motor from the driven machine)
- Aircraft tires (when the brakes are overheated, the pressure in the tire rises sharply. The fusible plug allows the pressure to escape and thus prevents the tire from exploding. The escaping gas also cools the overheated brakes)
hazards
General
The plumb bob changes over time. The melting point can consequently rise and thus render the fusible plug ineffective.
As a result, pure metals (tin) were used as solders, the material of the metal cylinder was optimized (zinc-free copper-tin-bronze) and regular replacement was prescribed.
The solder may not melt completely. This causes the fuse to leak instead of completely exposing the hole. As a result, the triggering of the fuse can go unnoticed.
In other applications, multiple fusible plugs may be required.
In addition to the fusible plug, a thermal switch can be attached.
Steam locomotives / steam boilers
The opening that the molten solder releases is insufficient to relieve the pressure in the steam container. As soon as the fusible plug trips, the fire under the boiler must be removed or extinguished. If the triggering of the fusible safety plug is not noticed or the fire is not removed, the boiler may explode. In locomotives, the fusible plug was therefore installed in the area of the fire box so that the outflowing boiler water extinguishes the firing as much as possible.
Alternatives
- Thermal switches
swell
- ↑ http://www.ite-tools.com/de/ategorie/messing-und-stahlverschraubungen-npt-und-sae-gewinde/messingfittings/verbindstopfen
- ↑ a b Archived copy ( memento of the original from March 5, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
